• Molecules and Cells
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• 제38권2호
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• pp.138-144
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• 2015

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

• The Korean Journal of Physiology and Pharmacology
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• 제22권4호
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• pp.379-389
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• 2018

A nucleobase adenine is a fundamental component of nucleic acids and adenine nucleotides. Various biological roles of adenine have been discovered. It is not produced from degradation of adenine nucleotides in mammals but produced mainly during polyamine synthesis by dividing cells. Anti-inflammatory roles of adenine have been supported in IgE-mediated allergic reactions, immunological functions of lymphocytes and dextran sodium sulfate-induced colitis. However adenine effects on Toll-like receptor 4 (TLR4)-mediated inflammation by lipopolysaccharide (LPS), a cell wall component of Gram negative bacteria, is not examined. Here we investigated anti-inflammatory roles of adenine in LPS-stimulated immune cells, including a macrophage cell line RAW264.7 and bone marrow derived mast cells (BMMCs) and peritoneal cells in mice. In RAW264.7 cells stimulated with LPS, adenine inhibited production of pro-inflammatory cytokines $TNF-{\alpha}$ and IL-6 and inflammatory lipid mediators, prostaglandin $E_2$ and leukotriene $B_4$. Adenine impeded signaling pathways eliciting production of these inflammatory mediators. It suppressed $I{\kappa}B$ phosphorylation, nuclear translocation of nuclear factor ${\kappa}B$ ($NF-{\kappa}B$), phosphorylation of Akt and mitogen activated protein kinases (MAPKs) JNK and ERK. Although adenine raised cellular AMP which could activate AMP-dependent protein kinase (AMPK), the enzyme activity was not enhanced. In BMMCs, adenine inhibited the LPS-induced production of $TNF-{\alpha}$, IL-6 and IL-13 and also hindered phosphorylation of $NF-{\kappa}B$ and Akt. In peritoneal cavity, adenine suppressed the LPS-induced production of $TNF-{\alpha}$ and IL-6 by peritoneal cells in mice. These results show that adenine attenuates the LPS-induced inflammatory reactions.

• 생명과학회지
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• 제23권5호
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• pp.689-697
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• 2013

오메가-3 지방산은 많은 암에서 세포독성을 나타낸다고 보고 되어 왔으나 구강암에 대한 연구는 전혀 없다. 이에 본 연구에서는 구강암세포에서 오메가-3 지방산 중 DHA의 세포독성 기전을 규명하여 다음과 같은 결과를 얻었다. DHA는 구강암 세포주 SCC-4 및 SCC-9의 증식을 농도 의존적으로 억제하였으며, FACS 분석, TUNEL assay 및 PARP cleavage 등에 의해 자가사멸을 유도함이 확인 되었다. 또한 DHA는 LC-3II 단백증가, GFP-LC-3 dot 형성 및 autophagic flux assay 등에 의해 자가포식도 유도됨이 규명되었다. SCC-9 세포에서 AMPK의 인산화는 DHA 에 의해 증가 하였으나, p-$AKT^{Thr308}$, p-$AKT^{Ser473}$ 및 mTOR단백양은 감소하였다. 이상의 결과로 DHA는 구강암세포에서 AMPK 활성증가 및 AKT 억제에 통한 mTOR 신호경로 차단에 따른 자가사멸 및 자가포식에 의해 세포독성을 나타낼 수 있음을 시사하며, 따라서 DHA는 구강암의 예방 및 치료에 유용하게 사용될 수 있으리라 생각된다.

• Natural Product Sciences
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• 제25권4호
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• pp.298-303
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• 2019

This study investigated the cytotoxic effects and mechanism of action of asiatic acid in pancreatic cancer cell lines. First, we confirmed the cell viability of MIA PaCa-2 and PANC-1 cells after asiatic acid administration for 48 and 72 h. The viability of MIA PaCa-2 and PANC-1 cells decreased in a dose-dependent manner following asiatic acid administration. To investigate the underlying mechanism, we performed a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, annexin V assay, and western blotting. Asiatic acid induced apoptosis and autophagy through activation of AMP-activated protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) in MIA PaCa-2 cells. Finally, the expression of miR-17 and miR-21, known as oncogenes in pancreatic cancer, was decreased by asiatic acid. These results indicate that asiatic acid has potential as a new therapeutic agent against pancreatic cancer.

• 생명과학회지
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• 제30권10호
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• pp.835-843
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• 2020

비만은 이제 선진국 뿐만 아니라 개발도상국에서도 가장 문제가 되는 대사성 질환이다. 최근 치료보다는 예방에 중점을 두는 예방의학 시대가 도래함에 따라, 인슐린 저항성 비만과 당뇨병 등의 대사 증후군을 예방하기 위한 천연물들이 큰 관심을 받고 있다. 특히, 베타글루칸은 면역계와 혈중 콜레스테롤 조절에 이로운 효과가 있는 것으로 알려져 있지만 비만에 미치는 영향에 대해서는 완전히 밝혀지지 않았다. 이에 본 연구에서는 β-1,3/1,6-glucan의 함량이 전체 글루칸 함량의 90% 이상 되는 자체 개발 흑효모 균주 SM-2001 추출물(폴리칸)이 3T3-L1 지방전구세포의 지방세포 분화에 미치는 영향을 조사하였다. 폴리칸은 지방전구세포에서 지방축적과 GPDH 효소 활성을 억제하는 것으로 나타났다. 이는 폴리칸이 세포 내에서 지방의 축적을 조절하는 전사인자인 PPARγ와 C/EBPα의 하향조절과 세포 내 에너지 센서 역할을 하는 AMPK 효소의 인산화를 유도함으로써 항비만 효과를 발현하는 것으로 확인되었다. 본 연구를 통해 폴리칸의 항비만 효과를 확인하였으며, 향후 비만과 대사성 질환을 예방할 수 있는 식의약 소재로써 그 활용가치를 더욱 높일 수 있을 것으로 기대한다.

• 생명과학회지
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• 제27권2호
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• pp.155-163
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• 2017

상엽은 뽕나무 잎을 건조한 약재로서 항염증, 항당뇨, 미백, 항산화, 항박테리아, 항알러지 및 면역조절 등과 같은 여러 가지 약리작용을 하는 것으로 알려져 있으나 항비만 효능에 대한 연구는 부족한 실정이다. 본 연구에서는 상엽 에탄올 추출물(ethanol extracts of Mori Folium, EEMF)이 유발하는 항비만 효능을 확인하기 위하여 3T3-L1 지방전구세포가 지방세포로 분화되는 과정에서 EEMF가 어떠한 영향을 미치는 지를 조사하였다. 3T3-L1 지방전구세포의 분화유도 시 EEMF를 처리하였을 경우 지방세포의 특징인 지방방울의 수 및 지방함량이 농도의 존적으로 감소하였으며, triglyceride의 생성도 억제되는 것으로 나타났다. 또한 EEMF는 pro-adipogenic transcription factors인 SREBP-1c, $PPAR{\gamma}$, $C/EBP{\alpha}$ 및 $C/EBP{\beta}$ 의 발현억제와 함께 adipocyte-specific genes인 aP2 및 Leptin의 발현억제도 유발하는 것으로 조사되었다. 특히 EEMF는 AMPK 및 ACC의 인산화를 억제하는 것으로 나타났지만 AMPK 억제제인 compound C를 이용하여 AMPK의 활성을 억제하였을 경우 EEMF에 의하여 유발되는 pro-adipogenic transcription factors 및 adipocyte-specific genes의 억제현상이 회복되었다. 이상의 결과에서 EEMF가 유발하는 adipogenesis의 억제는 AMPK signaling pathway의 활성화를 통하여 유발된다는 것을 알 수 있었으며, 추가적인 연구를 통하여 상엽에 함유되어 있는 유효성분에 대한 분석이 필요할 것으로 생각된다.

• 한국식품영양과학회지
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• 제43권11호
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• pp.1681-1687
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• 2014

FCEE를 3T3-L1 전지방세포의 분화과정 중에 처리한 후, FCEE가 지방의 축적에 미치는 영향을 확인하였다. FCEE($200{\mu}g/mL$)를 세포에 처리한 후 Oil Red O 염색법과 AdipoRed 형광염색법을 이용한 지방 축적과 세포내 중성지방 함량을 측정한 결과, 무처리한 지방세포와 비교하여 각각 10.2%, 13.7% 유의하게 감소하는 것을 확인하였다. 이러한 결과에 대한 기작을 확인하고자 포도당 유입량과 유리 글리세롤 방출량을 측정하였다. FCEE($200{\mu}g/mL$) 처리 시 지방세포와 비교하여 포도당 유입량이 36.6% 유의적으로 감소하였으며, 유리 글리세롤 방출량도 8일째에 유의적으로 감소하였다. 이는 지방세포의 분화과정 중에 FCEE의 처리로 분화가 억제되어 지방구의 형성이 억제되고 배양액으로 배출되는 유리 글리세롤의 총량이 감소한 것으로 판단된다. 이러한 결과가 지방세포 분화의 억제에 의한 것인지 판단하기 위해 지방 형성 관련인자의 mRNA 발현량을 측정하였다. FCEE($200{\mu}g/mL$)의 처리로 AMPK mRNA 발현량은 지방세포와 비교하여 3배 증가하였으며, SREBP-1c, $C/EBP{\alpha}$와 $PPAR{\gamma}$ mRNA 발현량은 각각 0.6, 0.6 및 0.8배 감소하는 것을 확인하였다. 이상의 결과들로부터 FCEE는 지방 합성을 억제하는 활성을 보유하고 있는 바, 향후 항비만 기능성 식품소재로 활용될 수 있을 것으로 사료된다.

• 동의생리병리학회지
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• 제27권6호
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• pp.802-808
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• 2013

Here we tried to uncover the potential anti-lipogenic effect and the underlying mechanism of Phaseolus angularis seed in a cellular model of nonalcoholic fatty liver disease (NAFLD) induced in HepG2 cells. Ethanol extract of Phaseolus angularis seed (JSD) was prepared. HepG2 cells were incubated in palmitate containing media to induce intracellular lipid accumulation, and co-treated with JSD for 16 hrs before examine intracellular lipid content. In control group, the cells were not co-treated with JSD. We measured the effects of JSD on liver X receptor ${\alpha}$ ($LXR{\alpha}$) and sterol regulatory element-binding transcription factor-1c (SREBP-1c) expression, transcription level of lipogenic genes, including acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), and AMP-activated protein kinase (AMPK) activation in HepG2 cells. JSD markedly reduced palmitate-induced intracellular lipid accumulation in HepG2 cells. JSD suppressed $LXR{\alpha}$/SREBP-1c expression, and SREBP-1c mediated induction of ACC, FAS, and SCD-1. Furthermore, JSD activated AMPK, which plays a major role in the control of hepatic lipid metabolism. Taken together, it is suggested that JSD has a potential to alleviate hepatic steatosis, at least in part, by suppressing $LXR{\alpha}$/SREBP-1c mediated induction of lipogenic genes. In addtion, the anti-lipogenic potential may be associated with activation of AMPK. Therefore, the Phaseolus angularis seed could be applied as a potential therapeutics for NAFLD with additional clinical studies.

• 대한한의학방제학회지
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• 제23권2호
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• pp.189-198
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• 2015

Objectives : Sparganii Rhizoma is frequently used in traditional herbal medicine for treatment of blood stasis, amenorrhea and functional dyspepsia and has been reported to exhibit anti-oxidant, anti-proliferation and anti-angiogenesis peoperties. In this study, we investigated the cytoprotective effect and underlying mechanism of Sparganii Rhizoma water extract (SRE) against oxidative stress-induced mitochondrial dysfunction and apoptosis in hepatocyte. Methods : To determine the effects of SRE on oxidative stress, we induced synergistic cytotoxicity by co-treatment of arachidonic acid (AA) and iron in the HepG2 cell, a human derived hepatocyte cell line. Results : Treatment of SRE increased relative cell viability and altered the expression levels of apoptosis-related proteins such as Bcl-xL, Bcl-2 and procaspase-3. And SRE also inhibited the mitochondrial dysfunction and excessive reactive oxygen species production induced by AA+iron. In addition, SRE activated of AMP-activated protein kinase (AMPK), a potential target for cytoprotection, by increasing the phosphorylation of AMPKα at Thr-172. Morever, SRE increased phosphorylation of acetyl-CoA carboxylase, a direct downstream target of AMPK. Conclusion : These results indicated that SRE has the ability to protect against oxidative stress-induced hepatocyte damage, which may be mediated with AMPK pathway.

• 한방재활의학과학회지
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• 제31권2호
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• pp.1-14
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• 2021

Objectives We evaluated the improving effects of Taeksa-tang (TST) using 3T3-L1 cells and C57BL/6 mice were fed on a high-fat diet. Methods The anti-radical activities of TST were studied using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid). The content of total polyphenol was measured using Folin-Ciocalteu reagent, whereas aluminum chloride colorimetric method was used for the content of total flavonoid. Moreover, the factors related to lipid profile and the protein expressions such as 𝛽-oxidation and anti-oxidant enzyme were analyzed using serum and western blotting of 3T3-L1 cells. Additionally, we examined lipolysis through glycerol appearance in mouse adipose tissue. Results TST treatment showed strong free radical scavenging activities with half maximal inhibitory concentration and the presence of a amount of total polyphenol and total flavonoid. TST treatment significantly increased factors related to 𝛽-oxidation such as carnitine palmitoyl transferase-1 and uncoupling protein 2 via the phosphorlyation of liver kinase B1 (LKB1) and AMP-activated protein kinase (AMPK). Moreover, the protein expressions of anti-oxidant enzyme and lipolysis were significantly elevated by TST administration. In addition, TST supplementation lowered serum malondialdehyde, triglyceride, and total cholesterol levels compared with the control group. Taken together, these data suggest that TST treatment regulated lipid parameters via the increase of 𝛽-oxidation by LKB1-AMPK signaling pathway. Conclusions TST may have a potential remedy in the prevention and treatment of obesity. Therefore, this study may provide the scientific basis for TST use.